Dispersive X-ray Analysis Research Articles

Amino-induced cadmium metal–organic framework based on thiazole ligand as a heterogeneous catalyst for the epoxidation of alkenes

Selective epoxidation of olefins is of high interest in the chemical industry due to the many applications of epoxides. This study reports on the synthesis of Cd-MOF, [Cd(DPTTZ)(5-AIP)] (IUST-1) (where DPTTZ = 2, 5-di (pyridine-4-yl) thiazolo [5, 4-d] thiazole, 5-AIP = 5-Aminoisophthalic acid), by a reflux method, which can be considered as a fast and simple process. The morphology and structure of the synthesized IUST-1 were determined by using FE-SEM (Field Emission Scanning Electron Microscopy), EDX (Energy Dispersive Analysis of X-ray), Mapping (Elemental Mapping), CHNS (Elemental analysis), XRD (X-Ray Diffraction), FT-IR (Fourier Transform Infrared), and TGA (Thermo Gravimetric Analysis). The epoxidation of cyclooctene was investigated using the activity of catalytic IUST-1. The results showed that in the presence of tert-butyl hydroperoxide and CCl4 in a 1:2 alkene/oxidant ratio, a high epoxide yield (99.8%) was obtained. In addition, IUST-1 can be easily separated by simple filtration and recycled five times successfully with a slight decrease in activity. This compound has some advantages such as high yield, short reaction time, and ease of reuse, which make it a suitable heterogeneous catalyst for the epoxidation of cyclooctene.

Effects of carbon nanotubes-based composites on the corrosion protection and mechanical properties of polymer coating in chloride environment

Carbon nanotubes (CNTs) possess excellent mechanical, thermal, electrical, electrochemical and optical properties. The combination of tungsten disulphide (WS2) and 3-aminopropyltriethoxysilane (APTES) with carbon nanotubes (CNTs) has improved the anticorrosive and mechanical capabilities of poly(p-phenylenediamine) (PpPD) coatings. Scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX), Transmission electron microscopy (TEM), Thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and X-Ray diffraction (XRD) techniques were used to characterize the composites such as APTES/CNTs, CNTs/WS2, and APTES/CNTs-WS2. As a result, the dielectric constant of PpPD was raised by 82 times at 102 Hz with the addition of just 0.6% APTES/CNTs-WS2. The APTES/CNTs-WS2 composite demonstrate improved anticorrosive and mechanical performance of the PpPD coating, according to electrochemical methods and mechanical testing. With a water contact angle (WCA) of 157°, this material is highly hydrophobic. Additionally, the PpPD-APTES/CNTs-WS2 was discovered to have significantly stronger resistance (17989 kΩ.cm2) than pure PpPD (101 kΩ.cm2), as well as significantly higher microhardness and tensile strength. The structure of the PpPD-APTES/CNTs-WS2 nanocomposite plays major role in enhancing the mechanical and anticorrosion properties. As a result, the PpPD-APTES/CNTs-WS2 nanocomposite may be used as a covering for solar panel frames.

Tio2 and Nickel Coatings on Resistance Welding Electodrs to exetended Life Using Chemical Vapour Desposition Process

TiO2/Ni coating has been deposited onto the electrodes by chemical vapour deposition to improve electrode life during resistance welding of Zn- coated steels. However, welding results revealed that molten Zn penetrates into coating through the cracks and then reacts with substrate copper alloy to form brasses. In the present work, laser treatment was performed on the TiO2/Ni coated electrodes to eliminate cracks formed in the as-deposited TiO2/Ni coating. In addition, a chemical vapour deposition of Ni, TiO2/Ni and Ni has also been carried out to improve coating quality. On the other hand, a Ti coating was also investigated. Those coatings were characterized by electro-microscopy, energy- dispersive X-ray analysis, X-ray diffraction and micro-hardness tests. The results showed that cracks within the as-deposited TiO2/Ni coating could be eliminated with the use of laser treatment and chemical vapour deposition process. However, softening of copper substrate after laser treatment was a problem that restricted welding performance. Welding tests showed that the multi-layer TiO2/Ni coating acted as a better barrier to decrease alloying between the copper alloy and molten Zn as well as pitting (erosion) of electrode. The TiO2 coating demonstrates its potential application on the electrode to further improve the electrode’s life Key Word: Electrode; Molecular; Titanium; Nanotechnology; Nickel.

Morphological and elemental analysis of termite mound and ant nest in agriculturally prominent area

Soil management is important for the farmers to improve the crop yield. In nature some invertebrates serve as bioindicators and biomonitors. Biogenic structure built by insects is important for controlling soil erosion and water reserves. Ants and termites nest architecture along with the elemental analysis was studied to evaluate soil health and possible threats imposed by heavy metals in the area. The soil samples were collected and analyzed for various parameters. Systematic study of porosity, composition, and nutritional values of soil in ant nest and termite mound were done. The Atomic Absorption Spectrophotometer and Inductively Coupled Plasma Mass Spectrophotometer studies showed that ant nest and termite mound samples were found to contain elements viz., zinc, selenium, lead, cadmium, nickel drought and chromium. Based on Scanning Electron Microscope-Energy Dispersive Analysis of X-rays, the size of soil samples collected from ant nest and termite were found to be 27.77 nm and 25.56 nm, respectively. The corrosion resistant zirconium and titanium metals were detected in 0.68 and 0.39% concentration in ant nest and termite mound samples, respectively, representing the insect house as a possible source of rich metals. The ant nest and termite mound materials contain quartz, microcline, kaolinite, and clay minerals. Ant nests and termite mounds can thus be used as hydrological indicators to address the problems of soil erosion.

Low-cost flame synthesized La2/3Cu3Ti4O12 electro-ceramic and extensive investigation on electrical, impedance, modulus, and optical properties

An environmentally-friendly synthesis route and low-cost starting materials are more appropriate for the production of ceramic materials at the industry level. With this concern we prepared the La2/3Cu3Ti4O12(LCTO), which is isostructural of CaCu3Ti4O12 (CCTO), using the low-cost TiO2 instead of a high-cost of titanium source (titanium isopropoxide or titanium chloride) using a low-cost wet-chemical route. Although, there are lots of synthetic methods reported for LCTO fabrication in terms of duration, cheap reagents, energy consumption, feasibility, etc. The present method is far better than the others. The prepared ceramic samples were sintered at 1050 °C/12 h and studied their structural, morphology and impedance, and modulus studies for further confirmation. The prepared LCTO ceramic shows the pure phase with the cubic type of morphology. The homogenous distribution of all the elements was observed through dispersive X-ray analysis. X-ray photoelectron spectroscopy studies revels that La is in +3 oxidation state, Cu is in a +2 oxidation state, and Ti is multiple (+3 and + 4) oxidation state. The LCTO ceramic displayed the very high dielectric constant (∼3852) and dielectric loss (0.322), at 1 kHz and at room temperature. Calculated the activation energy using the impedance and modulus data and it shows the superior to that of CCTO ceramic synthesized by the same method. The prepared samples exhibited Debye-type relaxation, which is evoked from the impedance and modulus studies. The calculated optical energy bandgap of LCTO (2.06 eV) is found to be lesser than that of the well-known structure of perovskites (BaTiO3 (3.28 eV), PbTiO3 (3.18 eV), LiNbO3 (3.78 eV) and BiFeO3 (2.67 eV) as well as structure of spinel CoCr2O4 (3.10 eV) and LuFe2O4 (2.18 eV)) materials.

The use of scanning electron microscopy (SEM) and energy dispersiveX-ray analysis (EDXA) as a measurement tool for EMPs tasks, guidelines

In a variety of European countries SEM/EDXA based methods are widely used for the measurements and judgements relating thereof regarding asbestos analysis. Most of these methods are used also for other fibrous particles, commonly indicated as Elongate Mineral Particles (EMPs).The span of guidelines reflects the broad use of SEM/EDXA as an analytical method. Guidelines regarding air measurements both for ambient and indoor air are well established. These methods are widely used as is shown in a proficiency testing scheme, organized by the British Health and Safety Executive (HSL) with participants from countries all over Europe and some countries from Asia and Africa. For workplaces a similar guideline with a reduced sensitivity is available, allowing measurements in higher dust concentrations. Features of the methods like analytical sensitivity, detection limits and measurement uncertainty are discussed.For material analysis we apply different analytical methods, using SEM/EDXA as a final step. They are different both in sample preparation and sensitivity. Most of the methods are qualitative or “semi-quantitative” and thought for the analysis of commercial asbestos containing products mainly. If quantitative analysis based on EDXA is used for identification other EMPs can be identified as well. An important tool is the morphological impression of the fibers or structures in the SEM in addition.Changes in regulations which may be expected, will modify some of the methods. Especially lowered Threshold Limit Values (TLV's) in occupational air measurements are difficult to achieve.

Vegetable Oil-Based Pentaerythritol Ester for Industrial Air Compressor Applications: A Tribological Investigation

Biolubricants are being developed more frequently as a result of environmental issues, which also improve performance and lessen friction and wear. This study seeks to examine the effects of commercial compressor oil-SAE30, and its blend with pentaerythritol ester (PE) derived from vegetable oil on tribological properties. Two sequential transesterification processes were used to create the pentaerythritol ester made from vegetable oil utilizing the ultrasonic irradiation method. Using an air compressor lubricant, load, and sliding speed for each experimental run, a pin-on-disc tribometer is utilized to examine the friction and wear characteristics of the material. According to the experimental findings, PE 75 (75 vol.% - PE and 25 vol.% - SAE30) performs better than PE and SAE30 in terms of minimum coefficient of friction (COF) and specific wear rate (SWR) under high loads and high sliding speeds. Furthermore, scanning electron microscope (SEM) and Energy Dispersive Analysis of X-Ray (EDAX) analyses were used to examine the morphology behavior of the pin surfaces. Due to the coating that covers the specimen's surface, PE 75 compressor oil displays smoother surfaces than other lubricated surfaces.

High yield synthesis and study of Cu substitution on characteristics and dielectric properties of MgO nanostructures

High-permittivity materials are becoming more popular due to the electrical and electronic industrial development. Single composition materials are well known to fall short of high permittivity requirements. So, in this article, we report pure and Cu (5%, 7%, 9%, and 11%) doped MgO nanostructures synthesized by reverse micelle method and study of their dielectric properties. Energy Dispersive Analysis of X-rays (EDAX), Powder X-ray Diffraction (PXRD), diffused reflectance UV–Vis spectroscopy (DR-UV-Vis), Dynamic Light Scattering (DLS), photoluminescence (PL), Raman spectroscopy and Broadband Dielectric Spectroscopy (BDS) are among the characterization methods used. Each synthesized sample crystallizes in cubic crystal system. As Cu doping increases from 5% to 11%, the average crystallite size dwindles from 22 to 10 nm. The bandgap is reduced from 5.71 eV to 2.58 eV as per the optical results from DR-UV-VIS spectroscopy. The intensity and surface defects are correlated by PL spectra. Raman peak shifts to the higher angle side, which is related to XRD and associated with a reduction in average crystallite size. For pure and all doping concentrations, the dielectric constant and the dissipation factor decreases with the increment in frequency which is a peculiar behaviour of dielectric materials.

Microstructural and wear properties of WC-12Co cemented carbide fabricated by direct energy deposition

The microstructural and wear properties of WC–12Co (wt.%) cemented carbide bulk material manufactured by additive manufacturing direct energy deposition (DED) process were investigated and compared to those of WC-12Co coating material fabricated by high-velocity oxygen fuel (HVOF) thermal spray process. The feedstock powder, DED and HVOF materials were analyzed using scanning electron microscopy/energy dispersive x-ray analysis (SEM/EDAX), X-ray diffraction (XRD) and an electron back-scattered diffraction (EBSD) technique. WC and α-Co phases were observed in the initial WC-12Co cemented carbide powder feedstock. After the DED process, WC phase growth and M12C phase were identified. However, the amount of M12C phase decreased after the HVOF process. The DED material had relatively higher porosity (BD: 11.58%; PD: 10.23%) as compared with HVOF (porosity: 1.66%). The hardness of the HVOF sample was measured as 1429 ± 49 HV, which was much higher than that of the DED (BD:1373 ± 68 HV, SD1: 1352 ± 62 HV) sample, due to the existence of porosity in the DED sample. A pin-on-disc tribometer was used to measure wear rates and coefficients of friction. The wear-worn surfaces were analyzed using SEM with an energy-dispersive spectrometer. The wear test results indicated that the DED material exhibited a lower wear rate (higher wear resistance) and a lower friction coefficient than those of the HVOF material. The difference in the wear behaviour of the DED and HVOF materials could be explained in terms of differences in WC size, the extent of reaction and decarburization during spraying, and the formation of the high oxide content.

Synthesis and characterization of strontium tartrate tetrahydrate crystal using silica gel method

In the present study, strontium tartrate tetrahydrate crystals were grown using the silica gel method. Optimum growth parameters were obtained by varying molar concentration, volume of upper reactant solution, and pH of gel mixture at ambient temperature (31 °C). Large size crystal (9 × 8 × 4 mm3) of strontium tartrate tetrahydrate were obtained when the pH of the gel mixture was 4.2 and upper reactant had a molar concentration of 1.5 M and volume of 20 ml. As grown crystal was characterized using different techniques viz. Powder X-ray Diffraction (PXRD), Fourier Transform Infrared spectroscopy (FTIR), Energy Dispersive Analysis of X-ray (EDAX), and UV–vis spectral analysis. Analysis of Powder X-ray diffraction data carried out in the 2θ range 10°–60° revealed that as grown crystal had an orthorhombic structure with space group P2 2 2 and unit cell parameters a = 9.8865 Å, b = 10.0448 Å, c = 9.5186 Å, α = β = γ = 90°. Various vibrational peaks of hydroxyl group (OH) at wavenumber 3170.42, 3384.44, 3536.72 cm−1, carbonyl (CO) group at 1601.88 cm−1 were observed in FTIR spectroscopy. One peculiar peak at 478.2 cm−1 where one O− and was replaced by Sr2+ was also obtained in FTIR spectroscopy suggesting formation of strontium tartrate crystal. Energy dispersive analysis of X-ray confirms the presence of expected major elements like strontium, carbon, and oxygen in the crystal. UV–vis transmission spectrum of strontium tartrate tetrahydrate crystals was recorded in the wavelength range of 190 to 1100 nm. The energy bandgap estimated from transmission data is 5.64 eV. Non-linear Optical (NLO) competence of STT crystal is observed at 532 nm. The electrical property of pelletized samples was studied by dielectric measurement in the frequency range of 20 Hz–2 MHz at room temperature. It is observed that dielectric loss is very low at higher frequency.

In vitro determination of the remineralizing potential and cytotoxicity of non-fluoride dental varnish containing bioactive glass, eggshell, and eggshell membrane.

This study compares in vitro remineralization potential and cytotoxicity of fluoride-free varnish combinations containing bioactive glass, eggshell, and membrane powder and fluoride varnish formulations on artificial caries lesions. Artificial caries lesions were formed in two windows on third molars. One of the windows was coated with one of the following varnish formulations: FV (fluoride varnish), F-BAGV (fluoride and bioactive glass containing varnish), BAGV (bioactive glass containing varnish), EPV (eggshell powder containing varnish), EMP-EPV (eggshell membrane protein and eggshell powder containing varnish), STMP-EMP-EPV (sodium trimetaphosphate-treated eggshell membrane protein and eggshell powder containing varnish). The samples were remineralized, then investigated under scanning electron microscopy, and elemental analyses were performed by X-ray dispersive analysis (EDX). In addition, the traditional colorimetric tetrazolium-based reduction assay (XTT) and the modern impedance-based real-time cell analysis system (RTCA) were used to investigate their cytotoxicity. The varnish applied area's Ca/P ratio was lower than stoichiometric hydroxyapatite except for EPV (1.66) and STMP-EMP-EPV (1.67) groups. Undiluted extracts of all varnishes, 1:2 dilutions of FV and F-BAGV groups were cytotoxic in XTT assay. In RTCA, the normalised cell index of the EMP-EPV and STMP-EMP-EPV groups was higher than the control group. Bioactive glass, eggshell, eggshell membrane proteins and STMP-treated eggshell and eggshell membrane protein containing varnish have similar remineralizing effect to fluoride-containing varnish on demineralized enamel. Integrating biological or bioactive components instead of fluoride into the dental varnishes might reduce cytotoxicity.

Synthesis of Tartaric Acid based Polymer Nanocomposite Incorporated with Copper Oxide Nanoparticles with Antibacterial Activity

The copper oxide nanoparticles were synthesized using Brassaia actinophylla (B. actinophylla) flower extract by solution combustion method. The poly(tartaric acid-co-diethylene glycol-co-acrylic acid (TDA) hydrogel was prepared using tartaric acid (T), diethylene glycol (D) and acrylic acid (A). The synthesized CuO nanoparticles were introduced into TDA hydrogel and the polymer nanocomposite TDA-CuO was obtained. The UV-peak was observed at 270 nm for TDA-CuO nanocomposite and for TDA no peak found. Fourier transform infrared (FT-IR) peak obtained at 432 cm-1 confirmed the presence of CuO nanoparticles in the hydrogel. The nanoparticles size 25-35 nm was confirmed by transmission electron microscope (TEM) and the morphology was examined by scanning electron microscopy (SEM) analysis. The percentage of copper and oxygen was analyzed by energy dispersive X-ray analysis (EDAX) spectrum where the percentage of copper is 2.4%. The thermal stability of TDA and TDA-CuO hydrogel was confirmed by thermogravimetric analysis (TGA). The antibacterial activity was performed against two Gram-positive Staphylococcus aureus and Bacillus subtilis and two Gram-negative Escherichia coli, Klebsiella pneumonia bacterial strains at various concentrations 25, 50, 75 and 100 μL by agar well diffusion method. The Gram-positive bacterial strains showed highest antibacterial activity than Gram-negative bacterial strain at highest concentration 100 μg/mL.

Study of the structural, morphological and optical properties of ZnSe doped with Yb3+

A wurtzite phase of Zn 1−x Yb x Se (0 ≤ x ≤ 1.8) nanoparticles was synthesized through photo assisted chemical bath deposition. Glancing angle X-ray diffraction disclosed a hexagonal wurtzite crystal structure. The crystallite size (D) of undoped ZnSe was estimated 24.40 nm and then gradually decreased to 4.66 nm, after Yb 3+ doping. Scanning electron microscopy images revealed that with an increase in the Yb 3+ concentration, the thin film morphology transformed from Nano-flakes to spherical particles. The expected elements were confirmed by elemental energy X-ray dispersive analysis. Raman spectroscopy revealed the existence of two distinct optical phonon peaks induced by first- and second-order longitudinal vibration peak located at 257 and 500 cm -1 , respectively. UV–visible spectroscopy elucidated that the absorption spectra showed that the band gap energy for undoped ZnSe thin films can be tuned in the range of 2.76 - 3.12 by varying Yb 3+ concentration. Photoluminescence analysis revealed two emission and shoulder peaks located at 3.19 eV, 2.37 eV and 1.70 eV, which were ascribed to the band-to-band and imperfections of ZnSe, respectively. Chromaticity investigations revealed that the blue emission color was dependent on the concentration of Yb 3+ . The results suggest that Zn 1−x Yb x Se (0 ≤ x ≤ 1.8) is a promising candidate for blue-light emitting phosphor. The data that support the findings of this study are available from the corresponding author upon reasonable request.

Tuberculosis detection from raw sputum samples using Au-electroplated screen-printed electrodes as E-DNA sensor.

Tuberculosis (TB) remains a leading cause of death globally, especially in underdeveloped nations. The main impediment to TB eradication is a lack of efficient diagnostic tools for disease diagnosis. In this work, label free and ultrasensitive electrochemical DNA biosensor for detecting Mycobacterium tuberculosis has been developed based on the electrodeposition of gold nanoparticles on the surface of carbon screen-printed carbon electrode (Zensors) for signal amplification. Particularly, screen-printed electrodes were modified by electrochemical deposition of Au to enhance the conductivity and facilitate the immobilization of ssDNA probes via Au-S bonds. The electrochemically modified SPEs were characterized using Scanning electron microscopy/Energy Dispersive X-Ray Analysis (SEM/EDX) and X-Ray Diffraction (XRD). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques were used to investigate the DNA hybridization between single-stranded (ssDNA) probe and target DNA (tDNA). Under the ideal conditions, DPV exhibited a correlation coefficient R2 = 0.97, when analyzed with different tDNA concentrations. The proposed DNA biosensor exhibits a good detection range from 2 to 10nm with a low detection limit of 1.91nm, as well as high selectivity that, under ideal conditions, distinguishes non-complementary DNA from perfectly matched tDNA. By eliminating the need for DNA purification, this work paves the path for creating disposable biosensors capable of detecting DNA from raw sputum samples.

Investigation of electron-phonon interaction in Pure and Indium doped MoS2 using temperature dependent Raman Spectra

Direct vapor phase synthesis technique was used to grow the bulk InxMo1-xS2 (x = 0, 0.05, 0.1). The grown material has hexagonal structure with P63/mmc space group. Electron-Phonon interaction in bulk InxMo1-xS2 (x = 0, 0.05, 0.1) were studied using Raman spectroscopy. First order mode i.e. A1g and E2g and second order mode i.e. b-mode were observed in bulk InxMo1-xS2 (x = 0, 0.05, 0.1) crystals. Temperature dependent Raman spectroscopy over the temperature range -180 °C to 240 °C shows the peak shifting. The higher sulfur void in bulk MoS2 as corelate to that of indium doped MoS2was responsible for excessive electron concentration. This study was supported by Energy Dispersive Analysis of X-ray (EDAX) and powder X-ray Diffraction (XRD) on bulk InxMo1-xS2 (x = 0, 0.05, 0.1).

The Polyol Process and the Synthesis of ζ Intermetallic Compound Ag5Sn0.9.

The present work concerns the intermetallic compound (IMC) existing in the Ag-Sn system and its potential use in electronics as attachment materials allowing the adhesion of the chip to the substrate forming the power module. First, we present the synthesis protocol in polyol medium of a compound with the chemical formula Ag5Sn0.9 belonging to the solid solution of composition located between 9 and 16 at.% Sn, known as solid solution ζ (or ζ-Ag4Sn). This phase corresponds to the peritectic invariant point at 724 °C. Differential thermal analysis and X-ray dispersive analysis confirm the single-phased (monocrystalline) nature of the Ag5Sn0.9 powder issued after synthesis. Scanning electron microscopy shows that Ag5Sn0.9 particles are spherical, and range in submicronic size of around 0.18 μm. X-ray diffraction analysis reveals that the ζ phase mostly exists under the two allotropic varieties (orthorhombic symmetry and hexagonal symmetry) with however a slight excess of the hexagonal variety (60% for the hexagonal variety and 40% for the orthorhombic variety). The lattice parameters resulting from this study for the two allotropic varieties are in good agreement with the Hume-Rothery rules.

A Study on Some Structural Aspects of PVA/PbS and PVA/PbS/ZnO Core/Shell Nanocomposites by Varying Different Reaction Parameters

This paper reports the synthesis and analysis of the characterization results of PbS and PbS/ZnO core/shell nanoparticles embedded in Polyvinyl Alcohol (PVA) matrix. The technique adopted in this work is wet chemical synthesis of PVA/PbS and PVA/PbS/ZnO core/shell nanoparticles. In total, two different sets of samples comprising of nine samples have been synthesized by altering parameters like PVA concentration and shell thickness for the PVA/PbS and PVA/PbS/ZnO samples, respectively. Various characterization techniques are used to analyze the influence of alteration of matrix concentration and shell thickness upon the as-synthesized nanoparticles. The techniques include UV-Vis Spectroscopy (UV-vis), Photoluminescence (PL) Spectroscopy, X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Analysis of X-Rays (EDAX) and Transmission Electron Microscopy (TEM). Results of the characterization techniques confirm the formation of nanoparticles of PbS and PbS/ZnO, respectively.

Machinability behaviors of synthesized beryllium composite

Currently, it is difficult to attain the composite with high quality material behaviors. The synthesized Titanium carbide based beryllium composite fulfills the need of excellent material behaviors. Titanium Carbide (TiC) particulate reinforced beryllium composite is synthesized through stir casting method as well as characterization of material has been studied by using Energy Dispersive Analysis of X-rays (EDAX) and Scanning Electron Microscope (SEM). The ultrasonic machining behaviors of the beryllium composite were evaluated using different input constraints such as power rating, abrasive size and frequency. Based on the input constraints, rate of metal removal was evaluated. The optimal factor was used to enhance the machinability behaviors using Taguchi approach.

Electrochemical Detection of Nitrite Ions Using PEDOT Based Films

Poly (3,4-ethylenedioxythiophene) (PEDOT) is an important conducting polymer that is widely studied for applications in photovoltaic devices, thermoelectric materials, batteries, capacitors and sensors [1]. In the field of sensors, PEDOT and PEDOT composites synthesized by chemical and electrochemical methods have been used for the detection of organic and inorganic analytes [2]. In particular, the performance of the composites of PEDOT with nanomaterials (mono and bi-metallic nanoparticles, graphene and nanotubes) has been thoroughly investigated in the last years because the incorporation of those nanostructures can significantly improve the sensing properties of the pristine polymer [3,4]. However, to the best of our knowledge the effect of the content of hollow PdAu nanoparticles in PEDOT composites for the detection of nitrite, an important environmental pollutant, has not been reported before.In this work, PEDOT films were prepared by cyclic voltammetry and under amperometric and potentiostatic conditions from a solution of EDOT, LiClO4 and SDS (sodium dodecyl suphate). The films were characterized by scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX). 500 nm- and 300 nm-thick PEDOT films deposited on glassy carbon were used for the electrochemical detection of nitrite by differential pulse voltammetry. 500 nm-thick films shown a higher sensitivity towards NO2 - ions (0.027 μA μM-1). Hollow nanoparticles of gold and palladium were synthesized by a galvanic replacement reaction using Na2PdCl4. PEDOT films were codeposited with the hollow PdAu nanoparticles at constant potential. The performance of the composites with different contents of the bimetallic nanoparticles (3,6,12,15,24 and 30% of the total mass of nanoparticles) were evaluated for the detection of nitrite ions in the range of 50 to 250 μM nitrite. All composites exhibited a higher performance in comparison to PEDOT films mainly in the range of 50 to 112.5 μM.Figure 1.- SEM PEDOT films produced by (a) potentiostatic deposition, (b) constant current, (c) cyclic voltammetry and (d) DPV curves of nitrite detection with PEDOT + 15% mass percent of PdAu nanoparticles suspension Figure 1

Effects of different Bismuth concentrations of InSbBi crystals grown by Bridgman technique

InSb1-xBix (x = 0, 0.005, 0.010, 0.015) crystals are grown by vertical Bridgman technique using single-zone resistive heating furnace. The main objective of this paper is to study the improvement of thermoelectric quality factors by different concentrations of Bismuth (Bi) in InSbBi crystals. EDAX (Energy Dispersive Analysis of X-rays) confirms that the grown crystals are pure and show the presence of In, Sb, and Bi in proportion. Powder X-ray diffractogram confirms the cubic zinc blend structure of these crystals with space group F-43m and all the diffraction peaks are matched well to the standard JCPDS-ICDD No. 6-0208. Raman spectra are recorded from 80 K to 300 K and Raman mapping spectra at room temperature for all above crystals have shown the presence of TO mode at 179.91 cm−1 and LO mode at 190.16 cm−1. The sharpness and intensity of Raman spectra have clearly reflected the purity and quality of the grown crystals. The electrical conductivity σ is found to increase slowly upto 450 K and then increases linearly upto 600 K and above that, it gets saturated in all crystals. The Seebeck coefficient remains negative showing that these crystals are n-type semiconductor and its value is found to be increased to −200 μV/K for InSb0.985Bi0.015 in comparison to −150 μV/K for pure InSb near 600 K. From the lattice thermal conductivity, power factor and thermoelectric figure of merit i.e. ZT calculations, it is concluded that InSb0.985Bi0.015 at 670 K gives the highest value of ZT = 0.45 in comparison to other grown crystals.